The invention relates to a needle-less injector having a housing comprising:                a chamber defined within said injector for containing liquid to be injected;        a liquid outlet for said chamber positioned at the front end of the injector;        a dispensing member in contact with the liquid in said chamber and movable in a first direction to reduce the volume of said chamber to cause the liquid contained therein to be expelled through said liquid outlet;        drive means for actuating said injector.        
Such a needle-less injector is known from WO 98/13085.
The known needle-less injector has a housing that is essentially unitary and is further characterized in that it utilises an impacting member arranged to strike said dispensing member to cause movement thereof in said first direction and that the drive means are connected to the impacting member for actuating the injector.
A problem with this known needle-less injector is that in order to secure continued operation for a prolonged time-span the construction of the known needle-less injector should be heavy. A further disadvantage is that the utilization of the impacting member to strike the dispensing member to cause its movement is very inefficient in terms of utilization of the available energy.
The invention aims in improving the known needle-less injector and addressing the above-mentioned problems.